ImageQt does not work as expected in PyQt5

[driscollis]

What did you do?

Attempted to use ImageQt to load a Pillow image in a PyQt5 application

What did you expect to happen?

I expected the image to load correctly. There are no errors, but it does not load the image in PyQt5 correctly.

What actually happened?

The image loaded as a mostly white image with kind of ghost image of the actual photo (see screenshot). I have attached the PyQt5 and PySide6 code, including screenshots from when I ran both files.

Note: The same code works in PySide6, but not in PyQt5.

What are your OS, Python and Pillow versions?

• OS: MacOS Mojave and Windows 10
• Python: Python 3.9
• Pillow: 8.0.0
  

import sys

from PIL import Image, ImageQt
from PyQt5.QtGui import QPixmap, QImage
from PyQt5.QtWidgets import QWidget, QLabel
from PyQt5.QtWidgets import QVBoxLayout, QApplication


class ImageViewer(QWidget):

    def __init__(self):
        QWidget.__init__(self)
        self.setWindowTitle("PyQt Image Viewer")

        # Open up image in Pillow
        image = Image.open("pink_flower.jpg")
        qt_image = ImageQt.ImageQt(image)
        pixmap = QPixmap.fromImage(qt_image)

        self.image_label = QLabel('')
        self.image_label.setPixmap(pixmap)

        self.main_layout = QVBoxLayout()
        self.main_layout.addWidget(self.image_label)
        self.setLayout(self.main_layout)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    viewer = ImageViewer()
    viewer.show()
    app.exec_()

pyqt_pillow_issue.zip

[radarhere]

Ok, got it. You're hitting this bug

Pillow/src/PIL/ImageQt.py

Lines 203 to 205 in fdd8b68

	# Fix some strange bug that causes
	if im.mode == "RGB":
	im = im.convert("RGBA")

If I change your code to

        # Open up image in Pillow
        image = Image.open("pink_flower.jpg")
        pixmap = ImageQt.toqpixmap(image)

then it works.

[driscollis]

Huh. That's interesting. I know I tried that, but I didn't remove the pixmap = QPixmap.fromImage(qt_image) line, which raises an error if left in there.

This definitely works if you remove that line too.

[driscollis]

Thanks for looking into this and finding the error so quickly!

[radarhere]

I've created #5268 to change Pillow so that your original code works.

[driscollis]

Thanks for looking into this. I appreciate it!